POS0173 GENDER DIFFERENCES IN TREATMENT RESPONSE IN PATIENTS WITH RHEUMATOID ARTHRITIS TREATED WITH TUMOR NECROSIS FACTOR INHIBITOR: A COHORT STUDY FROM THE DANBIO REGISTRY
Authors: K. B. Lauridsen, K. Duch, A. S. Mortensen, R. Cordtz, S. Kristensen, M. L. Hetland, L. Dreyer
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> TNF-inhibitors (TNFI) have improved the treatment of rheumatoid arthritis (RA) over the last two decades, but it is uncertain how much gender affects treatment response and drug adherence. <h3>Objectives</h3> The aim of this population-based study is to investigate effect of gender overall and across different age groups on treatment response and drug adherence in patients with RA treated with their first TNFI. <h3>Methods</h3> The study is an observational, nationwide cohort study using the DANBIO register linked by patients' unique civil registration number to The Danish Civil Registration System and The Danish National Prescription Registry. RA patients starting their first TNFI between 1<sup>st</sup> of January 2006 and 31<sup>st</sup> of December 2020 were included. Modified Poisson regression with robust variance estimator was used to calculate the relative risk (RR) with 95% confidence interval (95% CI) of having a good EULAR response at 4 and 12 months, respectively, comparing men to women. Linear regression was used to estimate mean difference in DAS28-CRP. The data was also analyzed in age groups to display a possible age-dependent gender effect. To quantify drug adherence for men compared to women, a crude and adjusted cause-specific Cox regression for treatment termination was performed. Hazard ratios (HR) are presented with 95% CI for 0-1, &gt;1-3 and &gt;3-5 years after TNFi treatment start. The Aalen-Johansen estimator was presented to illustrate cause-specific treatment termination. <h3>Results</h3> From DANBIO, 7386 RA patients starting their first TNFI were identified; and of these 5523 (75%) were women. Women had higher DAS28-CRP at baseline, 4 and 12 months, than men. At 4 months no significant difference in treatment responses was observed, but a tendency of better response in men compared to women was seen among patients ≤50 years (Table 1). At 12 months visit the EULAR over all good response rate was significantly higher among men, RR adjusted was 1.13 (1.05;1.21). The same trend was seen in all age groups at 12 months though not statistically significant. The hazard for termination of first TNFI treatment due to no effect, adverse events, infections, cancer or reason not stated was lower in men compared to women. HR within the first year was 0.90 (0.83;0.96), 1-3 years 0.91 (0.83;0.99), and from 3-5 years 0.93 (0.81;1.06), and did not change when adjusting for age, baseline DAS28-CRP, disease duration, co-treatment with scDMARD, and seropositivity. 10 years drug adherence is shown in figure 1. <h3>Conclusion</h3> After 4 and 12 months of treatment with first TNFI women have slightly higher DAS28-CRP and overall lower chance of achieving EULAR good response. In addition, women have an increased risk of discontinuation which deserves further attention. <h3>Acknowledgements</h3> We will like to thank patients and all rheumatologic departments in Denmark for their contribution of data in DANBIO. <h3>Disclosure of Interests</h3> Karen Buch Lauridsen Speakers bureau: Thermo Fisher Scientific, Kirsten Duch: None declared, Anders Sandermann Mortensen: None declared, René Cordtz Employee of: Is employed by IQVIA outside the submitted work, Salome Kristensen: None declared, Merete Lund Hetland Grant/research support from: have recieved Research grants from Abbvie, Biogen, BMS, Celltrion, Eli Lilly, Janssen Biologics B.V, Lundbeck Fonden, MSD, Medac, Pfizer, Roche, Samsung Biopies, Sandoz, Novartis, Lene Dreyer Speakers bureau: has received speakers fee from Eli Lilly, Galderma, and Janssen, Grant/research support from: has received research grants from BMS (outside the present work).